The use of endoscopes for diagnostic and therapeutic purposes is widespread. For example, there are upper endoscopes for examination of the esophagus, stomach and duodenum, colonoscopes for the examination of the colon, angioscopes for vascular examination, bronchoscopes for examining the bronchi, laparoscopes for examining the peritoneal cavity, and arthroscopes for the examination of joint spaces. The following discussion applies to all of these types of endoscopes.
An endoscope for examining the bronchial tract and conducting transbronchial biopsies is a good example of the usefulness of endoscopic technology. These devices, known as flexible bronchoscopes, are widely used in diagnosing pulmonary diseases since they are capable of reaching the more distal bronchi in the bronchial tract. To properly navigate and view a bronchial area, the bronchoscope is generally structured to contain a fiber optic bundle within the elongated probe section. Alternatively, the bronchoscope may utilize other means to view the bronchial area, such as a video device positioned within the bronchoscope. In addition to providing a direct viewing capability, flexible bronchoscopes generally possess a means to remove tissue samples, or other material from the bronchial tract for biopsy or culture purposes. Tissue samples for biopsy purposes may be collected using a biopsy forceps extending from the distal end of the bronchoscope or by brushing the suspect area to capture cellular material for subsequent microscopic examination. Another commonly used technique to collect cellular material is to wash, or lavage, the suspect area. When a lavage procedure is used, a solution is injected into the bronchial passage and subsequently withdrawn by suction through the distal end of the broncoscope to capture cellular material. Following withdrawal of the lavage fluid, the cellular material may be subjected to a cytological examination or culture.
One difficulty encountered in the use of endoscopes is continuously maintaining the endoscopic probe in a selected location within a body passage during the examination. Movement of the endoscopic probe while it is positioned within a body passage may occur for a number of reasons. For example, movement of the endoscope may occur due to an unintended bodily movement of the operator while the patient is undergoing the examination, or by an involuntary movement of the patient in response to the examination. Once the distal end of the endoscope has been dislodged from its intended location, it must be carefully repositioned before the examination may be resumed. Movement of the endoscope within a body passage is particularly pronounced during bronchoscopic examinations, since the patient must continue to breathe during the examination. Further, involuntary bronchospasmodic events within the bronchial passages may occur during the examination that will disrupt the location of the distal end of the bronchoscope. A significant additional difficulty resulting from unintended patient movement may arise when a biopsy procedure is conducted. Since a biopsy forceps or brush is generally used, an uncontrolled or unintended cutting of tissue in the passage due to patient movement may lead to hemoptysis. Moreover, since the biopsy forceps, or brush may reach and perforate the pleura, pneumothorax may also occur.
Still another difficulty encountered in the use of endoscopes for diagnostic purposes is the inability to sealably isolate a portion of the endoscope from the remainder of the body passage during an endoscopic examination. To facilitate internal viewing of a passage, for example, the fluid occupying the cavity is generally removed by means of a suction channel in the endoscope, which may be followed by the introduction of a gas through an additional channel in the endoscope to distend the internal space. Other endoscopic applications may require that a fluid be retained within the portion of the body passage that has been sealably isolated. For example, in transbronchial diagnostic procedures such as bronchoalveolar lavage, the bronchoscope is used to gently irrigate the air spaces in a distal air passage with a solution. Isolation of the solution to the region surrounding the distal end of the bronchoscope is required so that cellular samples removed during the lavage are sufficiently localized to be of diagnostic value. In particular, when collecting samples by lavage for use in the diagnosis of infectious pulmonary diseases, the sample must not be contaminated by bacterial or other agents transported to the distal end of the probe by the unrestrained movement of the solution through the passage.
Yet another difficulty encountered in the use of endoscopes occurs when the endoscope must be positioned at a relatively deep location within a body passage, so that a relatively long portion of the endoscope must be inserted into the patient. In such cases, the endoscope may be resistant to small, or incremental movements within the passage. Moreover, in certain cases, the endoscope length may develop sufficient resistance to further inward movement, so that the endoscope is prevented from extending to the intended location. Similar difficulties may also occur when the passage is relatively short, but includes relatively highly curved segments. Since the operator is generally limited to positional manipulations of exposed portions of the endoscope, considerable difficulty may be encountered in properly positioning the endoscope within body passages under these conditions.
Increasingly, endoscopes are used with disposable sheaths that are positioned over the insertion tube of the endoscope to avoid the communication of disease from one patient to another. An additional advantage of the disposable sheath is that it allows the device to be used at more frequent intervals, since the need for lengthy cleaning and sterilization procedures is largely eliminated. Generally, the sheath is comprised of a flexible, thin, resilient material, such as latex, or other similar materials, that fits over and surrounds the insertion tube of the endoscope so the insertion tube is completely isolated from contaminants. The sheath is generally further comprised of a viewing window at the distal end, and may include a plurality of internal channels, or lumens, through which biopsy samples or fluids may be either introduced or removed. Accordingly, an additional difficulty encountered in the use of endoscopes concerns the incorporation of positioning and passage-blocking means into the disposable outer sheath.
Consequently, there exists a need in the art for an apparatus that will continuously maintain an endoscopic probe in a selected position within a body passage during the examination. In addition, the apparatus must be able to sealably close the passage to either retain fluids within a closed space, or to prevent a fluid from reoccupying the space during an examination. Further, there exists a need in the art for an apparatus that permits an endoscopic probe to be properly positioned within a long body passage, and/or where the passage is highly curved. Finally, the apparatus must be compatible with disposable sheaths used with endoscopes.